Cationization is being used to characterize polymers by SIMS which would otherwise be unstable under measurement conditions. The stabilization effect arises via the donation of a substrate cation to the molecular fragments. Single-crystals of CaF2, NaCl, KBr, and BaF2 are being tested to determine which exhibit the cationization behavior and to what extent the phenomenon occurs. Polyethylene oxide (PEO) and polymethylmethacrylate (PMMA) are the test polymers for the study.